Influence of Fiber Distribution and Interfacial Strength on Transverse Compressive Strength of Unidirectional Composites

Xiaopeng Wan,Guangmeng Yang,Meiying Zhao

doi:10.1051/jnwpu/20193730443

Abstract

The representative volume element(RVE) of the computational micromechanics is established with random fiber distribution being generated by random sequential expansion algorithm. The plasticity of matrix and interfacial decohesion are simulated by using Drucker-Prager model and cohesive zone model respectively. The effects of the random fiber distribution and interfacial strength on the transverse compressive strength of unidirectional composites are analyzed. The results show that the random fiber distribution is a factor to cause the instability of the transverse compressive strength. Meanwhile, the matrix plastic shear damage and non interfacial damage is dominated in compression failure. Therefore, the RVE model without interface element adopted can clearly predict the compressive strength and the damage process of unidirectional composites, which contributes to simplify the modeling without considering the value of interfacial parameters.

Highlights

The representative volume element( RVE) of the computational micromechanics is established with ran⁃ dom fiber distribution being generated by random sequential expansion algorithm
The results show that the random fiber distribution is a factor to cause the instability of the transverse compressive strength
The matrix plastic shear damage and non interfacial damage is domina⁃ ted in compression failure

Summary

Introduction

35 GPa,泊松比 vm = 0.35,拉伸强度 σmt 和压缩强度 σmc 分别为80 MPa和 120 MPa。对复合材料横向压缩力学性能的影响,选取界面强度 Tn0 分别为: a) M⁃C 准则的黏聚力图 4 进一步给出了界面强度为 140 MPa 时,复合材料在横向压缩载荷作用下的损伤断裂形貌。可以看出在横向压缩载荷作用下,复合材料最终形成与加载垂直方向成 48°的剪切断裂带。这与 M⁃C 弹塑性理论计算得到的基体断裂角 50.8°相吻合[5] ,说明基体剪切塑性断裂是引起复合材料横向压缩破坏的主要因素,而界面损伤只是在基体出现损伤的局部区域内由于应力集中引起的。由上述分析可知,复合材料在实际压缩破坏过程中,界面损伤不是导致材料破坏主要因素,此时继续增大界面强度仿真得到的复合材料横向压缩强度基本不再升高。因此本文采用一种忽略界面单元的有限元模型,用此简化的无界面单元模型仿真得到的复合材料横向压缩应力-应变曲线以及损伤破坏形貌如图 5 所示。可以看出,无界面单元模型预测的复合材料横向压缩强度为 142.9 MPa,与试验值最为吻合,误差仅为 1.4%。同时在横向压缩载荷作用下复合材料最终断裂形貌与界面强度为 140 MPa

Results

Conclusion